Estimate the Derivative of the Function $f ( x ) = \frac { x } { 3 } - 3$

Multiple Choice

Estimate the derivative of the function $f ( x ) = \frac { x } { 3 } - 3$ at the point $x = 3$ .

A) $-\frac{1}{5}$
B) $\frac { 1 } { 3 }$
C) $\frac { 1 } { 5 }$
D) $- \frac { 1 } { 3 }$
E) $\frac { 1 } { 6 }$